There are many situations in which atmospheric air is filtered while being brought into an enclosed space. Commercial buildings are a prominent example. Homes and vehicles are other examples.
Some kind of mechanical air filter is generally used, which accumulates the particulate material that is taken from the air. In commercial buildings in particular, it is a fairly universal practice to shut down the air circulation system from time to time, thus discontinuing the inflow of atmospheric air. A need then arises for periodic cleaning of the air filter, and also for disposing of the particulate material. This type of maintenance often requires hand labor. And if the maintenance were to be automated, a complex system of apparatus would be required.